This invention relates to a pipe coupling for connecting and sealing a joint between a pair of pipes as fluid conduits, and more particularly, to the coupling of the type as advantageously designed for automatically preventing excessive relative displacement or disconnection between a pair of connected pipes while maintaining a good sealing effect.
The joint between a pair of connected pipes is affected by various factors, that is, internal factors such as change in pressure or temperature of fluid which flows through the pipes, and/or external factors such as axial or torsional forces or transversal oscillations caused for example by earthquake. These factors occasionally cause displacement or disconnection between the jointed pipes.
For the purpose of producing and maintaining interconnection between a coupling body and the pipes, a combination of clamping pieces with cooperating clamping bolts or screws is utilized in one form of the conventional pipe couplings, as disclosed in Japanese Utility Model Application No. 41-105135 (Publication No. 45-7260, published Apr. 8, 1970). This type of conventional device comprises a plurality of spaced-apart cylindrical clamping pieces each embedded in and extending radially of an annular coupling body so as to be slidable within a certain limited range in the direction toward the center of the pipe, and a plurality of cooperating clamping bolts each supported by the coupling body and having a threaded shank extending coaxially of an associated clamping piece, so that, when the clamping bolt is tightened or turned, the bolt end forcibly pushes the associated clamping piece to slide axially thereof, resulting in that the serrated end wall of the clamping piece is pressed against the circumferential wall of the pipe in order to frictionally prevent undesirable relative displacement of the pipe. However, because of the above-discussed particular construction, this prior art device is, in fact, not so satisfactory not only in performing the expected interconnecting function but also in preventing damage to the pipes occurring when a considerably great axial force or a twisting force is applied to the joint between the pipes.
For the same purpose as mentioned above, a combination of a clamping ring with a plurality of clamping bolts or screws is utilized in another form of the conventional pipe couplings, as disclosed in Japanese Utility Model Application No. 47-79013 (Publication No. 54-24326, published Aug. 17, 1979), in which a split clamping ring is mounted on one of the pipes, so that, as the plurality of screws are tightened, the clamping ring, which is engaged with the screws, is compressed diametrically and pressed against the circumferential wall of the pipe. However, because the internal circumference of the ring, which is in tight contact with the circumferential wall of the pipe, has a smooth surface, the ring cannot hold its position relative to the pipe but is forced to axially slide on the circumferential wall of the pipe when a considerably great axial force is applied to the pipe.
It is, therefore, an object of the invention to eliminate the above discussed disadvantages in the conventional devices.
Another object is to provide an improved pipe coupling which is capable of producing and maintaining a firm interconnection between a pair of jointed pipes in response to changes in internal and/or external forces applied thereto.
A further object is to provide an improved pipe coupling which is simple in profile and good in appearance with less projections or protrusions.
A further object is to provide an improved pipe coupling which is very simple in construction with minimized number of parts and permits manufacture and maintenance at a low cost.
A still further object is to provide an improved pipe coupling having such a structure that permits an easy assemble with a deformable and self-sealing type sealing ring.
A yet further object is to provide an improved pipe coupling which is easy to handle and install at a job site and promotes efficiency in pipe connecting work.
Other object, features and advantages of the invention will become more fully apparent from the detailed description given hereinafter in connection with the accompanying drawings. It should be understood, however, that the detailed description and specific examples, which indicate preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.